Copper alloy.



llwrrnn dramas arnnrr lemon.

BERTRAND S. SUMMERS, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE WVESTERNELECTRIC CO., OF SAME PLACE.

COPPERALLOY.

. SPECIFICATION forming part of Letters Patent No. 680,819, dated August20, 1901. Application filed January 4, 1899. Serial No. 701,125- (Nospecimens.)

To whom it may concern:

Be it known that I, BERTRAND S. SUMMERS, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Copper Alloys, (CaseNo. 3,) of which the following is a full, clear, concise, and exactdescription.

My invention relates to an improved copper alloy which is designed,primarily, for use in the electrical art and which has the properties ofhigh electrical conductivity and of being readily cast.

The object of my said invention is to produce a metal combining theseobvious advantages.

I-Ieretofore it has been found impossible to obtain satisfactorycommercial castings of copper except when that metal is combined with arelatively large percentage of an alloying metal -as, for example,bronze or brass. It is well known that such alloys may be readily cast;but for electrical uses these metals are greatly inferior to copper,inasmuch as the electrical conductivity of an alloy is very much lessthan that of copper and cannot therefore be used for many purposes. Ihave, however, discovered a copper alloy which by reason of theproperties imparted by the addition of a small perecentage of magnesiumis nearly equal to pure copper for electrical purposes, while beingcapable of being readily cast to form any desired article of commerce.

The alloy of my invention, whose preparation I will now describe,consists of commercially-pure copper, to which has been added a verysmall percentage of magnesium.

The method which I preferably practice in preparing the alloy is asfollows: Commercially pure copper in any convenient form is placed in agraphite pot, the metal then being covered with charcoal and the lidplaced upon the pot. The graphite pots as thus prepared are placed in afurnace, where they are allowed to remain and be heated until the copperis perfectly fluid. At intervals during the heating more charcoal isadded to the pots in order to maintain the metal at all times beneath alayer of that material. When the pots and contents have beensufficiently heated,the lids are successively removed and magnesium isintroduced in the following manner: Magnesium provided with an externalprotective wrapper, for which I preferably use paper and sheet-asbestos,is tied upon a copper rod and forced beneath the surface of the heatedmetal, the molten mass being thoroughlystirred to secure an intimatemixture of the two metals. I have found that the proportions rangingbetween one-half and two ounces of magnesium to each one hundred poundsof copper are ordinarily the most advantageous in producing my alloy,although I have experimented with various other proportions of the twometals and secured satisfactory results, the quantity of magnesium useddepending somewhat upon the nature of the copper and the use for whichthe alloy is intended. Immediately after securing the thorough alloyingof the metals the pot is removed from the furnace and the molten metalis cast, care being taken to skim off the floating charcoal and anyslight surface impurities that may be present by means of copper orcarbon skimmers. It will be found that the copper alloy as thus preparedis capable of being satisfac torily cast and that such castings aresolid and free from porous ordefective portions so commonly found whenthe casting of copper is attempted. I have analyzed a number of castingsof my alloy as thus prepared and have found that the average amount ofmagnesium therein ranges from .02 to .09 per cent. On the other hand, myimproved alloy has an electrical conductivity of about ninety per cent.that of pure copper, its physical properties being practically identicalwith those of copper. For electrical purposes my alloy is very muchsuperior to any other copper alloy with which I am conversant, since itscasting properties are equal to any, while its conductivity remains verymuch higher than is found in other alloys. From my observations I haveconcluded that the magnesium serves to purge the copper from gaseous andother impurities, thus imparting to it the conditions required forcasting the metal in a state approximating commercial purity. It will beunderstood that the resulting product or alloy may Vary considerablywithout departing from the principles consisting of approximatelyone-tenth of one or spirit of my invention, the same contemper cent. ofmagnesium and commerciallyplating an alloy having substantially the purecopper.

properties of pure copper and which in ad- In witness whereof I hereuntosubscribe 5 dition may readily be cast. my name this 21st day ofDecember, A. D. 15

I therefore claim, and desire to secure by 1898. these Letters Patent,the following: BERTRAND S. SUMMERS.

The herein-described alloy having substan- Witnesses: tially theproperties of pure copper and being MINA L. SWORTWOUT, 1o capable ofbeing readily cast, the said alloy A. L. LAWRENCE.

